Compressor cycles on and off

toolmanmike said

I would be tempted to put another 1/2 pound in and see if it clears up. No bubbles in the sight glass and cool air out of the ducts doesn't necessarily mean it's fully charged. Duct temps can get down to the mid to upper 30's without freeze up. R12 systems can stand more freon before being overcharged. 134 systems will not tolerate overcharging.

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I say no. He's determined that it's cycling on the evap temp switch and not low pressure

Undercharged, the evap is not going to get the stat cold enough to cause this

Either what he's seeing is normal.........how often IS it cycling.......?

Or likely the stat itself is going bad

More on the stat? Not much too 'em. Read your shop manual.......it's a cap tube stat that has the tube in intimate contact with the evap coil

The only other thing I could think of is that if a door in the box is effed up and causing recirculation IE blocking airflow through the coil. This seems UNlikely given the description

These diagrams are actually from the '70 manual